Dynamical Study of Resistive States in Iron based Superconducting Material

Superconductivity in non-equilibrium regime remains under the focus of many studies. It attracted a lot of attention for its potential applications in different fields such as particle detection and photon detection. The current-induced breakdown in superconducting filament involves fundamental phenomena and advanced concepts like hot spot (HS), phase slips centers (PSC), and vortices [1-4]. We are proposing here to study the destruction of the superconductivity by an electrical current in iron based superconducting materials. The materials will be different combinations of iron arsenide and iron solenoids having critical temperature (Tc ) form 15 K to 30 K. Once the superconducting state is destroyed by the electrical current, the resistive state appears after a certain delay time (td) [ ]. The td will be measured experimentally at our lab. Destroying superconductivity at different temperature leads to different dissipation modes. By varying temperature, PSC and HS phases with their domains will be identified. The td values, thus observed at different temperatures, are investigated with the modified Time-Dependent Ginzburg-Landau (TDGL) theory. Using TDGL the heat escape time of the film on each substrate will be subsequently deduced. The escape time is the fundamental parameter and a key indicator of the performance of superconducting single photon detector device. In addition, we propose to study the microscopic mechanism of these materials by using Scanning Tunneling Microscopy (STM). The superconducting gap () will be extracted from the tunneling spectra by using extended Bardeen Cooper Schrieffer (BCS) theory for anisotropic s-wave paring. being the measure of binding energy of cooper pairs, it provides the information of paring mechanism, which is one of the burning questions of condensed matter physics at the moment. For that purpose, we are planning to cooperate with a collaborator, an academic laboratory overseas (Laboratoire Pierre Aigrain LPA-ENS, FParis-France), which is already active in the field of current-induced superconductivity breakdown and its modern applications such as single-particle detectors. The necessary instruments and expertise on electrical pulse measurements are available at KFUPM Physics Department, where many experimental works were being carried out earlier. Our work has been presented in international conferences and published in ISI journals.